Murphy still races his ’76 RT-2 in vintage events, riding it just as hard now as he did back then.

It
seems, with only a few exceptions, that not much is new to the dirt
bike world. Bold new graphics, sure. Fuel injection is “sort of” new but
dirt bikes have been developing that since the early ‘90s and airplanes
had fuel injection before WW2. But 1970 was different. The dirt bike
market – and subsequently, technology – was expanding at an
unprecedented rate. You name it, they’ve tried it. Perhaps the most
radical of all the early ‘70s designs came from a little company in New
Hampshire more famous for building unstoppable two-wheel drive ATVs.

Rokon’s weird two-wheel drive Rokon Trailbreakers were one thing, but
when Rokon decided to cash in on the expanding dirt bike market things
got really strange! The radical machine they came up was a clean-sheet
dirt bike design. Remember, this was an era of pipey, piston-port
two-strokes with hand-grenade reliability. Motocross riders had to be
clutch artists, constantly tap-dancing the shifter just to keep the
engines in their narrow powerband. Hop off a modern bike and onto a
vintage motocross bike and you’ll instantly develop respect for pro
riders of that era!

Instead of fighting that battle Rokon used a simple, reliable 340cc
Sachs snowmobile engine. Transmission? What could be easier to use than a
snowmobile-style Salsbury clutch? Twist and go. With an infinitely
variable transmission Rokon engineers didn’t have to worry about a peaky
powerband and could instead tune the engine for maximum power and
simply adjust the clutch to keep the engine revving at the power peak
all the time. A great idea, in theory at least, but would it work on a
dirt bike?